The aldabra atoll in the Seychelles is home to the Aldabra giant tortoise, one of the world's largest tortoises. These terrestrial creatures make their habitats in scrubs, mangrove swamps, coastal dunes and dense grasslands called platins.
The males are relatively larger in size than the females, with longer and thicker tails. They can weigh up to 250 kilograms and their dome-shaped shells can grow to about 1.2 meters across.
Covered by bony scales, their hindlegs are enormous and columnar, similar to those of an elephant. Their small pointed heads are supported by their long necks, which can extend up to one meter above the ground for feeding.
The Aldabra giant tortoise is a Zen master in living a slow, long life. It moves in an unhurried gait and sleeps for 18 hours a day. The average lifespan of the tortoise is over 100 years, with the record exceeding 150 years. During normal days in the Aldabra atoll, where the climate is hot and dry, the tortoises take mud baths to stay cool.
They also migrate to different habitats based on different seasons, moving toward open grasslands and scrub forests near the coasts during rainy seasons and various dwellings for dry days.
Chiefly herbivores, they feed on grasses, leaves and shoots from which they get their main supply of moisture. However, they also consume meat when available, and may even take in dead tortoises and feces. They can survive without food or water for a long period.
In terms of reproductive behavior, the slow-moving tortoise becomes sexually mature when its body size is large enough, rather than being old enough like most other species. It is ready for mating when it grows into half the size of a full grown-up.
Tortoise parents do not nurture their offspring. After a four-month incubation period, the young tortoises will hatch out and live independently.
Charles Darwin initiated the conservation work for the giant tortoises after his visit to Aldabra in the 1880s.
With the help of conservationists, the environment of the Aldabra atoll has been comprehensively protected. It has been designated a World Heritage site by the United Nations Educational, Scientific and Cultural Organization and it has become a thriving haven for hundreds of other animal and plant species.
Aldabra giant tortoises have also been introduced to other atolls of the Seychelles, Tanzania and Mauritius.
Despite their haven, Aldabra giant tortoises are now threatened again due to climate change.
The Aldabra atoll is only one to two meters above sea level. If temperatures continue to rise and melt ice and snow, by the year 2100, the oceans would have risen by about one meter.
The Aldabra giant tortoise is now listed as vulnerable on the International Union for Conservation of Nature Red List. Hence, it is time for us to act to lower carbon emissions and fight global warming, such as by reducing the use of air-conditioners.
You can meet these rare giant tortoises in person when Ocean Park Hong Kong reopens.